The present invention relates to cyclic pro-perfumes capable of releasing at least one fragrance raw material alcohol, preferably a tertiary fragrance raw material alcohol. The novel pro-perfumes of the present invention can be modified by the formulator to control the rate at which the fragrance raw material alcohol is released once the material is applied, for example, to human skin.
Humans have applied scents and fragrances to their skin since antiquity. Originally these aesthetically pleasing materials were commonly isolated in raw form as resins, gums or essential oils from natural sources, inter alia, the bark, roots, leaves and fruit of indigenous plants. These resins, gums, and oils were directly applied to the body or diluted with water or other solvent, including in some cases, wine. With the advent of modern chemistry, individual components responsible for the odor properties of these resins, gums and oils were isolated and subsequently characterized. Modern perfumery involves the artful compounding of fragrance materials to achieve novel fragrance compositions having defined xe2x80x9ccharacteristicsxe2x80x9d.
Many modem fragrances are no longer derived from natural sources but are synthesized by modern chemical methods as highly pure fragrance raw materials (FRM). These FRM""s are currently formulated to produce fine perfumes, colognes, eau de toilettes, after-shave lotions, and other personal fragrance compositions. Those skilled in the art of preparing these fragrance-containing compositions have categorized fragrances into three types based on their relative volatility; top, middle, and base notes.
Top, middle, and base notes each serve a different purpose in the blending of fragrances and when properly formulated produce a xe2x80x9cbalanced fragrancexe2x80x9d composition. Based on volatility, these notes are described by those skilled in the art as: the base notes having the most long lasting aroma; the middle notes, have a medium volatility; and the top notes are the most volatile. Key to successfully formulating a fragrance-containing composition is the precise balance between these three groups of materials producing a fragrance-containing composition that diffuses during its evaporation in a manner which has an aesthetic quality.
It has been the goal of those skilled in the art of perfumes and fragrances to provide aesthetically pleasant odor compositions wherein the initial top, middle, and base note balance is maintained for an extended period of time. Due to the uneven rate of evaporation of the components which comprise a fine perfume or fragrance, the initial fragrance may be quite different than the aroma perceived several hours later. This problem is solved in many different ways by the user. One method is to xe2x80x9cload upxe2x80x9d on the perfume initially and rely on the natural evaporation rate to diminish the fragrance to a suitable level several hours later when the desired effect is needed. Another method which is used is to continually renew the fragrance by reapplying small amounts of the perfume to the skin at short time intervals. Neither of these solutions is adequate to overcome the diminishing level of top and middle notes over time. In fact, base notes which are present over a protracted period by virtue of their low volatility, begin to accumulate with each xe2x80x9cre-freshingxe2x80x9d of perfume. After some time these base notes overwhelm the other fragrance notes and destroy the original fragrance balance.
However, despite these artful approaches and compensating for the physical properties of perfume ingredients, formulators have not been able to well control the rate at which fragrance raw materials, especially fragrance raw material alcohols, are released when applied, for example, on human skin, hair, etc. Therefore, there has been a long felt need for a means of releasing at least one fragrance raw material alcohol, preferably tertiary alcohols, at a controllable rate.
It has now been surprisingly discovered that the novel cyclic pro-perfumes, which are the subject matter of the present invention, can not only release fragrance raw material alcohols but can be modified to release said alcohols within a range of time desirable to the formulator. In addition, the cyclic pro-perfumes described herein are capable of delivering highly desirable tertiary alcohols.
The present invention meets the aforementioned needs in that it has been surprisingly discovered than certain cyclic pro-perfumes can be modified to release their fragrance raw material alcohols at variable rates after being exposed to an acid milieu inter alia human skin.
A first aspect of the present invention relates to cyclic pro-perfumes capable of releasing at least one fragrance raw material alcohol, said pro-perfumes having the formula: 
wherein xe2x80x94OR is a unit derived from a fragrance raw material alcohol; R1 is hydrogen, C1-C22 alkyl, C1-C22 alkenyl, C6-C12 aryl, C6-C22 alkylenearyl, C3-C20 substituted or unsubstituted alkyleneoxyalkyl, and mixtures thereof; R2, R3, R4, and R5 are each independently selected from hydrogen, C1-C30 substituted or unsubstituted linear alkyl, C3-C30 substituted or unsubstituted branched alkyl, C3-C30 substituted or unsubstituted cyclic alky, C2-C30 substituted or unsubstituted linear alkenyl, C3-C30 substituted or unsubstituted branched alkenyl, C3-C30 substituted or unsubstituted cyclic alkenyl, C2-C30 substituted or unsubstituted linear alkynyl, C3-C30 substituted or unsubstituted branched alkynyl, C6-C30 substituted or unsubstituted alkylenearyl, C6-C30 substituted or unsubstituted aryl, C2-C20 substituted or unsubstituted alkyleneoxy, C3-C20 substituted or unsubstituted alkyleneoxyalkyl, C7-C20 substituted or unsubstituted alkylenearyl, C6-C20 substituted or unsubstituted alkyleneoxyaryl, and mixtures thereof, or any two R2, R3, R4, or R5 can be taken together to form a fused ring or spiroannulated ring having from 3 to 8 carbons and optionally one or more heteroatoms in said ring, said ring is optionally further substituted by one or more C1-C22 alkyl, C1-C22 alkenyl, C6-C12 aryl, C6-C22 alkylenearyl units, and mixtures thereof, Y is xe2x80x94CR6R7xe2x80x94, Cxe2x95x90O, and mixtures thereof, wherein R6 and R7 are independently hydrogen, hydroxyl, nitro, nitrilo, C1-C30 substituted or unsubstituted linear alkyl, C3-C30 substituted or unsubstituted branched alkyl, C3-C30 substituted or unsubstituted cyclic alkyl, C2-C30 substituted or unsubstituted linear alkenyl, C3-C30 substituted or unsubstituted branched alkenyl, C3-C30 substituted or unsubstituted cyclic alkenyl, C2-C30 substituted or unsubstituted linear alkynyl, C3-C30 substituted or unsubstituted branched alkynyl, C6-C30 substituted or unsubstituted alkylenearyl, C6-C30 substituted or unsubstituted aryl, C2-C20 substituted or unsubstituted alkyleneoxy, C3-C20 substituted or unsubstituted alkyleneoxyalkyl, C7-C20 substituted or unsubstituted alkylenearyl, C6-C20 substituted or unsubstituted alkyleneoxyaryl, and mixtures thereof, or R6 and R7 can be taken together to form a spiroannulated ring or taken together with any R2, R3, R4, or R5 to form a fused ring, said spiroannulated or fused ring having from 3 to 8 carbons and optionally one or more heteroatoms in said ring, said ring further optionally substituted by one or more C1-C22 alkyl, C1-C22 alkenyl, C6-C12 aryl, C6-C22 alkylenearyl units, and mixtures thereof; n is from 0 to 3.
The present invention also relates to fine fragrance compositions inter alia perfumes, colognes, after shaves, and eau de toilettes comprising said cyclic pro-perfumes. In addition, personal care and personal hygiene articles may comprise the cyclic pro-perfumes described herein. Non-limiting examples of these personal care items include deodorants, body lotions or creams, sun tan lotions, and shampoos.
The present invention also relates to a fragrance delivery system which comprises at least one cyclic pro-perfume as described herein. Preferably said fragrance delivery system delivers at least one tertiary fragrance raw material alcohol. These and other objects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims.
All percentages, ratios and proportions herein are by weight, unless otherwise specified. All temperatures are in degrees Celsius (xc2x0 C.) unless otherwise specified. All documents cited are in relevant part, incorporated herein by reference.
The present invention relates to cyclic pro-perfumes capable of releasing at least one fragrance raw material alcohol. Surprisingly, the cyclic pro-perfumes of the present invention are capable of releasing in a controlled manner desirable tertiary perfume raw material alcohols inter alia linalool, ethyllinalool, dihydromyrcenol, and tetrahydrolinalool.
The pro-perfumes of the present invention are essentially orthoesters. Orthoesters, in general, may be considered to be xe2x80x9cacetalsxe2x80x9d of carboxylic acid esters which can be formed by the reaction of an ester with two equivalents of alcohol. Treatment of orthoesters with sufficient acid catalyst in the presence of moisture results in the xe2x80x9creversionxe2x80x9d of orthoesters back into a mixture of ester and alcohol. In the instance where the ester alcohol is not the same as the orthoester forming alcohol, and depending upon the structure and reactivity of the orthoester components, one of the alcohols released from the reversion reaction may be the original ester alcohol resulting in one of the xe2x80x9corthoester formingxe2x80x9d alcohols now comprising the ester. In this instance, xe2x80x9ctransesterificationxe2x80x9d has occurred.
Without wishing to be limited by theory, the release rate of the fragrance raw material alcohol from the cyclic orthoesters of the present invention may be controlled, for example, by adjusting, separately or in combination, either the relative basicity of the orthoester oxygen atoms in the cyclic moiety or the torsional ring strain of the resulting cyclic orthoesters. One result of these adjustments is to provide increased or decreased ring opening kinetics and thereby a means for regulating the release rate of the fragrance raw material alcohol.
Cyclic Pro-perfumes
The cyclic pro-perfumes of the present invention have the formula: 
wherein the moiety xe2x80x94OR is derived from a fragrance raw material alcohol having the general formula ROH. Non-limiting examples of fragrance raw material alcohols which can be suitably released by the cyclic pro-perfumes of the present invention include 2,4-dimethyl-3-cyclohexene-1-methanol (Floralol), 2,4-dimethyl cyclohexane methanol (Dihydro floralol), 5,6-dimethyl-1-methylethenylbicyclo-[2.2.1]hept-5-ene-2-methanol (Arbozol), 2,4,6-trimethyl-3-cyclohexene-1-methanol (Isocyclo geraniol), 4-(1-methylethyl)cyclohexanemethanol (Mayol), xcex1-3,3-trimethyl-2-norborane. methanol, 1,1-dimethyl-1-(4-methylcyclohex-3-enyl)methanol, 2-phenylethanol, 2-cyclohexyl ethanol, 2-(o-methylphenyl)-ethanol, 2-(m-methylphenyl)ethanol, 2-(p-methylphenyl)ethanol, 6,6-dimethylbicyclo-[3.1.]hept-2-ene-2-ethanol (nopol), 2-(4-methylphenoxy)ethanol, 3,3-dimethyl-xcex942-xcex2-norbornane ethanol, 2-methyl-2-cyclohexylethanol, 1-(4-isopropylcyclohexyl)-ethanol, 1-phenylethanol, 1,1-dimethyl-2-phenylethanol, 1,1-dimethyl-2-(4-methyl-phenyl)ethanol, 1-phenylpropanol, 3-phenylpropanol, 2-phenylpropanol (Hydrotropic Alcohol), 2-(cyclododecyl)propan-1-ol (Hydroxy-ambran), 2,2-dimethyl-3-(3-methylphenyl)propan-1-ol (Majantol), 2-methyl-3-phenylpropanol, 3-phenyl-2-propen-1-ol (cinnamyl alcohol), 2-methyl-3-phenyl-2-propen-1-ol (methylcinnamyl alcohol), xcex1-n-pentyl-3-phenyl-2-propen-1-ol (xcex1-amyl-cinnamyl alcohol), ethyl-3-hydroxy-3-phenyl propionate, 2-(4-methylphenyl)-2-propanol, 3-(4-methylcyclohex-3-ene)butanol, 2-methyl-4-(2,2,3-trimethyl-3-cyclopenten-1-yl)butanol, 2-ethyl4-(2,2,3-trimethyl-cyclopent-3-enyl)-2-buten-1-ol, 3-methyl-2-buten-1-ol, 2-methyl4-(2,2,3-trimethyl-3-cyclopenten-1-yl)-2-buten-1-ol, 3-hydroxy-2-butanone, ethyl 3-hydroxybutyrate, 4-phenyl-3-buten-2-ol, 2-methyl-4-phenylbutan-2-ol, 4-(4-hydroxyphenyl)butan-2-one, 4-(4-hydroxy-3-methoxyphenyl)butan-2-one, 3-methyl-pentanol, 3-methyl-3-penten-1-ol, 2-methyl-4-phenylpentanol (Pamplefleur), 3-methyl-5-phenylpentanol (Phenoxanol), 2-methyl-5-phenylpentanol, 2-methyl-5-(2,3-dimethyltricyclo[2.2.1.0(2,6)]hept-3-yl)-2-penten-1-ol (santalol), 4-methyl-1-phenyl-2-pentanol, (1-methyl-bicyclo[2.1.1]hepten-2-yl)-2-methylpent-1-en-3-ol, 3-methyl-1-phenylpentan-3-ol, 1 ,2-dimethyl-3-(1-methylethenyl)cyclopentan-1-ol, 2-isopropyl-5-methyl-2-hexenol, cis-3-hexen-1-ol, trans-2-hexen-1-ol, 2-isoproenyl-4-methyl4-hexen-1-ol (Lavandulol), 2-ethyl-2-prenyl-3-hexenol, 1-hydroxymethyl-4-iso-propenyl-1-cyclohexene (Dihydrocuminyl alcohol), 1-methyl4-isopropenycyclohex-6-en-2-ol (carvenol), 6-methyl-3-isopropenylcyclohexan-1-ol, 1-methyl4-iso-propenylcyclohexan-3-ol, 4-isopropyl-1-methylcyclohexan-3-ol, 4-tert-butylcyclo-hexanol, 2-tert-butylcyclohexanol, 2-tert-butyl4-methylcyclohexanol, 4-isopropyl-cyclohexanol, 4-methyl-1-(1-methylethyl)-3-cyclohexen-1-ol, 2-(5,6,6-trimethyl-2-norbornyl)cyclohexanol, isobornylcyclohexanol, 3,3,5-trimethylcyclohexanol, 1-methyl-4-isopropylcyclohexan-3-ol, 1,2-dimethyl-3-(1-methylethyl)cyclohexan-1-ol, heptanol, 2,4-dimethylheptan-1-ol, 2,4-dimethyl-2,6-heptandienol, 6,6-dimethyl-2-oxymethylbicyclo[3.1.1]hept-2-ene (myrtenol), 4-methyl-2,4-heptadien-1-ol, 3,4,5,6,6-pentamethyl-2-heptanol, 3,6-dimethyl-3-vinyl-5-hepten-2-ol, 6,6-dimethy-3-hydroxy-2-methylenebicyclo[3.1.1]heptane, 1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol, 2,6-dimethylheptan-2-ol, 2,6,6-trimethylbicyclo[1.3.3]heptan-2-ol, octanol, 2-octenol, 2-methyloctan-2-ol, 2-methyl-6-methylene-7-octen-2-ol (myrcenol), 7-methyloctan-1-ol, 3,7-dimethyl-6-octenol, 3,7-dimethyl-7-octenol, 3,7-dimethyl-6-octen-1-ol (citronellol), 3,7-dimethyl-2,6-octadien-1-ol (geraniol), 3,7-dimethyl-2,6-octadien-1-ol (nerol), 3,7-dimethyl-1,6-octadien-3-ol (linalool), 3,7-dimethyloctan-1-ol (pelagrol), 3,7-dimethyloctan-3-ol (tetrahydrolinalool), 2,4-octadien-1-ol, 3,7-dimethyl-6-octen-3-ol, 2,6-dimethyl-7-octen-2-ol (dihydromyrcenol), 2,6-dimethyl-5,7-octadien-2-ol, 4,7-dimethyl-4-vinyl-6-octen-3-ol, 3-methyloctan-3-ol, 2,6-dimethyloctan-2-ol, 2,6-dimethyloctan-3-ol, 3,6-dimethyloctan-3-ol, 2,6-dimethyl-7-octen-2-ol, 2,6-dimethyl-3,5-octadien-2-ol (muguol), 3-methyl-1-octen-3-ol, 7-hydroxy-3,7-dimethyloctanal, 3-nonanol, 2,6-nonadien-1-ol, cis-6-nonen-1-ol, 6,8-dimethylnonan-2-ol, 3-(hydroxymethyl)-2-nonanone, 2-nonen-1-ol, 2,4-nonadien-1-ol, 3,7-dimethyl-1,6-nonadien-3-ol (ethyllinalool), decanol, 9-decenol, 2-benzyl-M-dioxa-5-ol, 2-decen-1-ol, 2,4-decadien-1-ol, 4-methyl-3-decen-5-ol, 3,7,9-trimethyl-1,6-decadien-3-ol (isobutyl linallol), undecanol, 2-undecen-1-ol, 10-undecen-1-ol, 2-dodecen-1-ol, 2,4-dodecadien-1-ol, 2,7,11-trimethyl-2,6,10-dodecatrien-1-ol (farnesol), 3,7,11-trimethyl-1,6,10,-dodecatrien-3-ol, 3,7,11,15-tetramethylhexadec-2-en-1-ol (phytol), 3,7,11,15-tetramethylhexadecl-en-3-ol (iso phytol), benzyl alcohol, p-methoxy benzyl alcohol (anisyl alcohol), para-cymen-7-ol (cuminyl alcohol), 4-methyl benzyl alcohol, 3,4-methylenedioxy benzyl alcohol, methyl salicylate, benzyl salicylate, cis-3-hexenyl salicylate, n-pentyl salicylate, 2-phenylethyl salicylate, n-hexyl salicylate, 2-methyl-5-isopropylphenol, 4-ethyl-2-methoxyphenol, 4-allyl-2-methoxyphenol (eugenol), 2-methoxy-4-(1-propenyl)phenol (isoeugenol), 4-allyl-2,6-dimethoxy-phenol, 4-tert-butylphenol, 2-ethoxy-4-methylphenol, 2-methyl-4-vinylphenol, 2-isopropyl-5-methylphenol (thymol), pentyl-orthohydroxy benzoate, ethyl 2-hydroxy-benzoate, methyl 2,4-dihydroxy-3,6-dimethylbenzoate, 3b-hydroxy-5-methoxy-1-methylbenzene, 2-tert-butyl-4-methyl-1-hydroxybenzene, 1-ethoxy-2-hydroxy4-propenylbenzene, 4-hydrozytoluene, 4-hydroxy-3-methoxybenzaldehyde, 2-ethoxy4-hydroxybenzaldehyde, decahydro-2-naphthol, 2,5,5-trimethyl-octahydro-2-naphthol, 1,3,3-trimethyl-2-norbomanol (fenchol), 3a,4,5,6,7,7a-hexahydro-2,4-dimethyl4,7-methano-1H-inden-5-ol, 3a,4,5,6,7,7a-hexahydro-3,4-dimethyl4,7-methano-1H-inden-5-ol, 2-methyl-2-vinyl-5-(1-hydroxy-1-methylethyl)tetrahydrofuran, xcex2-caryophyllene alcohol, and mixtures thereof
Preferred fragrance raw material alcohols are tertiary alcohols inter alia 3,7-dimethyl-1,6-octadien-3-ol (linalool), 3,7-dimethyloctan-3-ol (tetrahydrolinalool), 3,7-dimethyl-1,6-nonadien-3-ol (ethyllinalool), and 2,6-dimethyl-7-octen-2-ol (dihydromyrcenol).
R1 is hydrogen, C1-C22 alkyl, C1-C22 alkenyl, C6-C12 aryl, C6-C22 alkylenearyl, C3-C20 substituted or unsubstituted alkyleneoxyalkyl,. and mixtures thereof Preferably R1 is hydrogen, C1-C4 alkyl, C7-C10 alkylenearyl; more preferably hydrogen, methyl, ethyl, propyl, iso-propyl, t-butyl, phenyl, substituted phenyl, benzyl and substituted benzyl.
R2, R3, R4, and R5 are each independently hydrogen, C1-C30 substituted or unsubstituted linear alkyl, C3-C30 substituted or unsubstituted branched alkyl, C3-C30 substituted or unsubstituted cyclic alkyl, C2-C30 substituted or unsubstituted linear alkenyl, C3-C30 substituted or unsubstituted branched alkenyl, C3-C30 substituted or unsubstituted cyclic alkenyl, C2-C30 substituted or unsubstituted linear alkynyl, C3-C30 substituted or unsubstituted branched alkynyl, C6-C30 substituted or unsubstituted alkylenearyl, C6-C30 substituted or unsubstituted aryl, C2-C20 substituted or unsubstituted alkyleneoxy, C3-C20 substituted or unsubstituted alkyleneoxyalkyl, C7-C20 substituted or unsubstituted alkylenearyl, C6-C20 substituted or unsubstituted alkyleneoxyaryl, and mixtures thereof. In addition, any two R2, R3, R4, or R5 units can be taken together to form a fused ring cyclic pro-perfume having from 3 to 8 carbon atoms and optionally one or more heteroatoms in the ring. An example of a fused ring cyclic pro-perfume includes the general formulae: 
The fused rings may also optionally comprise one or more heteroatoms, preferably oxygen, nitrogen, sulfur and mixtures thereof An example of a fused ring cyclic pro-perfume comprising a heteroatom has the formula: 
wherein R8 is independently hydrogen, C1-C22 alkyl, hydrogen, C1-C30 substituted or unsubstituted linear alkyl, C3-C30 substituted or unsubstituted branched alkyl, C3-C30 substituted or unsubstituted cyclic alkyl, C2-C30 substituted or unsubstituted linear alkenyl, C3-C30 substituted or unsubstituted branched alkenyl, C3-C30 substituted or unsubstituted cyclic alkenyl, C2-C30 substituted or unsubstituted linear alkynyl, C3-C30 substituted or unsubstituted branched alkynyl, C6-C30 substituted or unsubstituted alkylenearyl, C6-C30 substituted or unsubstituted aryl, C2-C20 substituted or unsubstituted alkyleneoxy, C3-C20 substituted or unsubstituted alkyleneoxyalkyl, C7-C20 substituted or unsubstituted alkylenearyl, C6-C20 substituted or unsubstituted alkyleneoxyaryl, or one or more saccharide units. Non-limiting examples of saccharide units according to the present invention include erythrose, threose, arabinose, ribose, lysose, xylose, glucose, mannose, allose, altrose, talose, galactose, idose, gulose, fiuctose, and combinations thereof. The saccharides of the present invention are preferably in the pyranose (closed ring) form, however, when in solution, an equilibrium may exist wherein some of the material may exist in the non-preferred ring opened form. Any number of saccharides can be linked together. For example, oligosaccharidexe2x80x94two or three saccharides or polysaccharidesxe2x80x94more than three saccharides, are suitable for use in the present invention.
The cyclic pro-perfumes of the present invention further comprise spiroannulated rings having from 3 to 8 carbon atoms and optionally one or more heteroatoms in the ring, examples of which have the general formulae: 
wherein said fused ring or spiroannulated ring cyclic pro-perfumes may have their rings further substituted by one or more units, said units are independently hydroxyl, C1-C22 alkoxy, C1-C22 alkyl, C1-C22 alkenyl, C6-C22 aryl, C6-C22 alkylenearyl units, and mixtures thereof. The fused rings may also comprise one or more aromatic rings, including heteroaromatic rings. Examples of aromatic and heteroaromatic rings include benzene, naphthalene, pyridine, quinoline, isoquinoline, etc.
Preferably R2, R3, R4, and R5 are selected such that said units comprise a vicinal diol or 1,3-type diol. For example, when taken together, R2, R3, R4, and R5 derive from diols non-limiting examples of which include 1,2-propanediol, 1,2-butanediol, 1,2-hexanediol, 1,2-octanediol, 1,3-hydroxyacetone, 1,3-octanediol. All of the preceding examples of diols include a hydroxy moiety at the terminus or the alkyl chain. However, as described herein below, non-terminal hydroxy diols are also preferred.
Spacing unit Y is xe2x80x94CR6R7xe2x80x94, Cxe2x95x90O, and mixtures thereof R6 and R7 are independently hydrogen (wherein the moiety xe2x80x94CR6R7xe2x80x94 is a methylene unit), hydroxyl, nitro, nitrilo, C1-C30 substituted or unsubstituted linear alkyl, C3-C30 substituted or unsubstituted branched alkyl, C3-C30 substituted or unsubstituted cyclic alkyl, C2-C30 substituted or unsubstituted linear alkenyl, C3-C30 substituted or unsubstituted branched alkenyl, C3-C30 substituted or unsubstituted cyclic alkenyl, C2-C30 substituted or unsubstituted linear alkynyl, C3-C30 substituted or unsubstituted branched alkynyl, C6-C30 substituted or unsubstituted alkylenearyl, C6-C30 substituted or unsubstituted aryl, C2-C20 substituted or unsubstituted alkyleneoxy, C3-C20 substituted or unsubstituted alkyleneoxyalkyl, C7-C20 substituted or unsubstituted alkylenearyl, C6-C20 substituted or unsubstituted alkyleneoxyaryl, and mixtures thereof, or R6 and R7 as described herein above can be taken together to form a spiroannulated ring or taken together with any R2, R3, R4, or R5 unit to form a fused ring, said spiroannulated or fused ring having from 3 to 8 carbons. In addition, the resulting spiroannulated or fused rings may be further substituted by one or more C1-C22 alkyl, C1-C22 alkenyl, C6-C12 aryl, C6-C22 alkylenearyl units, and mixtures thereof.
The index n is an integer from 0 to 3, preferably 0 or 1, more preferably 0.
For the purposes of the present invention substituted or unsubstituted alkyleneoxy units are defined as moieties having the formula: 
wherein R5 is hydrogen; R6 is hydrogen, methyl, ethyl, and mixtures thereof; the index x is from 1 to about 20.
For the purposes of the present invention substituted or unsubstituted alkyleneoxyalkyl are defined as moieties having the formula: 
wherein R5 is hydrogen, C1-C18 alkyl, C1-C4 alkoxy, and mixtures thereof; R6 is hydrogen, methyl, ethyl, and mixtures thereof; the index x is from 1 to about 20 and the index y is from 2 to about 30.
For the purposes of the present invention substituted or unsubstituted alkylenearyl units are defined as moieties having the formula: 
wherein R5 and R6 are each independently hydrogen, hydroxy, C1-C4 alkoxy, nitrilo, halogen, nitro, carboxyl (xe2x80x94CHO; xe2x80x94CO2H; xe2x80x94CO2Rxe2x80x2; xe2x80x94CONH2; xe2x80x94CONHRxe2x80x2; xe2x80x94CONRxe2x80x22; wherein Rxe2x80x2 is C1-C12 linear or branched alkyl), amino, alkylamino, and mixtures thereof, p is from 1 to about 34.
For the purposes of the present invention substituted or unsubstituted aryloxy units are defined as moieties having the formula: 
wherein R5 and R6 are each independently hydrogen, hydroxy, C1-C4 alkoxy, nitrilo, halogen, nitro, carboxyl (xe2x80x94CHO; xe2x80x94CO2H; xe2x80x94CO2Rxe2x80x2; xe2x80x94CONH2; xe2x80x94CONHRxe2x80x2; xe2x80x94CONRxe2x80x22; wherein Rxe2x80x2 is C1-C12 linear or branched alkyl), amino, alkylamino, and mixtures thereof.
For the purposes of the present invention substituted or unsubstituted alkyleneoxyaryl units are defined as moieties having the formula: 
wherein R5 and R6 are each independently hydrogen, hydroxy, C1-C4 alkoxy, nitrilo, halogen, nitro, carboxyl (xe2x80x94CHO; xe2x80x94CO2H; xe2x80x94CO2Rxe2x80x2; xe2x80x94CONH2; xe2x80x94CONHRxe2x80x2; xe2x80x94CONRxe2x80x22; wherein Rxe2x80x2 is C1-C12 linear or branched alkyl), amino, alkylamino, and mixtures thereof, q is from 1 to about 34.
For the purposes of the present invention substituted or unsubstituted oxyalkylenearyl units are defined as moieties having the formula: 
wherein R5 and R6 are each independently hydrogen, hydroxy, C1-C4 alkoxy, nitrilo, halogen, nitro, carboxyl (xe2x80x94CHO; xe2x80x94CO2H; xe2x80x94CO2Rxe2x80x2; xe2x80x94CONH2; xe2x80x94CONHRxe2x80x2; xe2x80x94CONRxe2x80x22; wherein Rxe2x80x2 is C1-C12 linear or branched alkyl), amino, alkylamino, and mixtures thereof, w is from 1 to about 34.
Not wishing to be limited by theory, a formulator wishing to increase the degree of torsional strain in the pro-perfume ring may, however, select a diol having two non-terminus alcohols, for example, 2,3-octanediol or 3,4-octandiol. The increase or decrease in the torsional strain of the cyclic pro-perfume ring provides the formulator with a means for adjusting the rate at which the fragrance raw material alcohol is released by the cyclic orthoester. For example, the two cyclic pro-perfumes having the formulae: 
will exhibit different release rates of perfume raw material alcohol ROH due in part to the torsional strain provided by the eclipsing interaction of the methyl group with the alkyl chain.
Fragrance Delivery System
The present invention further relates to fragrance delivery systems comprising:
a) at least one cyclic pro-perfume;
b) optionally one or more pro-perfumes, pro-fragrances, or pro-accords capable of releasing one or more fragrance raw materials, said fragrance raw materials selected from the group consisting of aldehydes, ketones, alcohols, esters, nitrites, nitro compounds, linear, branched and cyclic alkenes, ethers, and mixtures thereof;
c) optionally one or more fragrance raw materials; and
d) the balance carriers and adjunct ingredients.
The pro-perfumes, pro-fragrances, or pro-accords which are combinable with the cyclic pro-perfumes of the present invention are preferably the pro-accords. The term xe2x80x9caccordxe2x80x9d as used herein is defined as xe2x80x9ca mixture of two or more xe2x80x98fragrance raw materialsxe2x80x99 which are artfully combined to impart a pleasurable scent, odor, essence, or fragrance characteristicxe2x80x9d. Therefore a material which is a xe2x80x9cpro-accordxe2x80x9d is capable of releasing a mixture of fragrance raw materials or a fragrance accord. Non-limiting examples of pro-accords and pro-fragrances include orthoesters, acetals, ketals, orthocarbonates, and the like described herein below.
When formulated into a fragrance delivery system, the cyclic pro-perfumes of the present invention will comprise from about 0.1% to about 99%, preferably from about 1% to about 50% by weight, of said fragrance delivery system.
The fragrance delivery systems of the present invention preferably comprise the pro-accords described herein below. When present, said pro-accords comprise singly or as an admixture from 0.1% to about 99%, preferably from about 1% to about 50% by weight of the fragrance delivery system.
In addition, the fragrance delivery systems of the present invention further comprises carriers, fixatives, and other adjunct ingredients which can be added in any suitable amount or ratio to the cyclic pro-perfumes or the optional pro-accords which comprise the balance of the delivery system. Typical carriers are methanol, ethanol (preferred), iso-propanol, polyethylene glycol, as well as water in some instances. Fixatives serve to lower the volatility of certain top and middle notes in order to extend their contact time on skin. Adjunct ingredients include perfume raw material components which are essential oils and are therefore not a single chemical entity. In addition, the adjunct ingredients may be mixtures of synthetic fragrance raw materials which serve a further purpose in addition to providing a pleasurable odor.
Orthoesters
One class of preferred compounds useful as pro-accords according to the present invention are orthoesters having the formula: 
wherein hydrolysis of the orthoester releases fragrance raw material components according to the following scheme: 
wherein R is hydrogen, C1-C8 linear alkyl, C4-C20 branched alkyl, C6-C20 cyclic alkyl, C6-C20 branched cyclic alkyl, C6-C20 linear alkenyl, C6-C20 branched alkenyl, C6-C20 cyclic alkenyl, C6-C20 branched cyclic alkenyl, C6-C20 substituted or unsubstituted aryl, preferably the moieties which substitute the aryl units are alkyl moieties, and mixtures thereof, preferably R is hydrogen, methyl, ethyl, and phenyl. R1, R2 and R3 are independently C1-C20 linear, branched, or substituted alkyl; C2-C20 linear, branched, or substituted alkenyl; C5-C20 substituted or unsubstituted cyclic alkyl; C6-C20 substituted or unsubstituted aryl, C2-C40 substituted or unsubstituted alkyleneoxy; C3-C40 substituted or unsubstituted alkyleneoxyalkyl; C6-C40 substituted or unsubstituted alkylenearyl; C6-C32 substituted or unsubstituted aryloxy; C6-C40 substituted or unsubstituted alkyleneoxyaryl; C6-C40 oxyalkylenearyl; and mixtures thereof. By the term xe2x80x9csubstitutedxe2x80x9d herein is meant xe2x80x9ccompatible moieties which replace a hydrogen atomxe2x80x9d. Non-limiting examples of substituents are hydroxy, nitrilo, halogen, nitro, carboxyl (xe2x80x94CHO; xe2x80x94CO2H; xe2x80x94CO2Rxe2x80x2; xe2x80x94CONH2; xe2x80x94CONHRxe2x80x2; xe2x80x94CONRxe2x80x22; wherein Rxe2x80x2 is C1-C12 linear or branched alkyl), amino, C1-C12 mono- and dialkylamino, and mixtures thereof
Acetals and ketals
Another class of compound useful as pro-accords according to the present invention are acetals and ketals having the formula: 
wherein hydrolysis of the acetal or ketal releases one equivalent of aldehyde or ketone and two equivalents of alcohol according to the following scheme: 
wherein R is C1-C20 linear alkyl, C4-C20 branched alkyl, C6-C20 cyclic alkyl, C6-C20 branched cyclic alkyl, C6-C20 linear alkenyl, C6-C20 branched alkenyl, C6-C20 cyclic alkenyl, C6-C20 branched cyclic alkenyl, C6-C20 substituted or unsubstituted aryl, preferably the moieties which substitute the aryl units are alkyl moieties, and mixtures thereof R1 is hydrogen, R, or in the case wherein the pro-accord is a ketal, R and R1 can be taken together to form a ring. R2 and R3 are independently selected from the group consisting of C5-C20 linear, branched, or substituted alkyl; C4-C20 linear, branched, or substituted alkenyl; C5-C20 substituted or unsubstituted cyclic alkyl; C6-C20 substituted or unsubstituted aryl, C2-C40 substituted or unsubstituted alkyleneoxy; C3-C40 substituted or unsubstituted alkyleneoxyalkyl; C6-C40 substituted or unsubstituted alkylenearyl; C6-C32 substituted or unsubstituted aryloxy; C6-C40 substituted or unsubstituted alkyleneoxyaryl; C6-C40 oxyalkylenearyl; and mixtures thereof By the term xe2x80x9csubstitutedxe2x80x9d herein is meant xe2x80x9ccompatible moieties which replace a hydrogen atomxe2x80x9d. Non-limiting examples of substituents are hydroxy, nitrilo, halogen, nitro, carboxyl (xe2x80x94CHO; xe2x80x94CO2H; xe2x80x94CO2Rxe2x80x2; xe2x80x94CONH2; xe2x80x94CONHRxe2x80x2; xe2x80x94CONRxe2x80x22; wherein Rxe2x80x2 is C1-C12 linear or branched alkyl), amino, C1-C12 mono- and dialkylamino, and mixtures thereof
Orthocarbonates
Another class of preferred compounds useful as pro-accords according to the present invention are orthocarbonates having the formula: 
wherein hydrolysis of the orthoester releases the fragrance raw material components according to the following scheme: 
which can continue to hydrolyze and further release two equivalents of one or more fragrance raw material alcohol according to the following scheme: 
thereby providing up to four equivalents of fragrance raw material alcohol per equivalent of delivered orthocarbonate, wherein R1, R2, R3, and R4 are independently C1-C20 linear, branched, or substituted alkyl; C2-C20 linear, branched, or substituted alkenyl; C5-C20 substituted or unsubstituted cyclic alkyl; C6-C20 substituted or unsubstituted aryl, C2-C40 substituted or unsubstituted alkyleneoxy; C3-C40 substituted or unsubstituted alkyleneoxyalkyl; C6-C40 substituted or unsubstituted alkylenearyl; C6-C32 substituted or unsubstituted aryloxy; C6-C40 substituted or unsubstituted alkyleneoxyaryl; C6-C40 oxyalkylenearyl; and mixtures thereof. By the term xe2x80x9csubstitutedxe2x80x9d herein is meant xe2x80x9ccompatible moieties which replace a hydrogen atomxe2x80x9d. Non-limiting examples of substituents are hydroxy, nitrilo, halogen, nitro, carboxyl (xe2x80x94CHO; xe2x80x94CO2H; xe2x80x94CO2Rxe2x80x2; xe2x80x94CONH2; xe2x80x94CONHRxe2x80x2; xe2x80x94CONRxe2x80x22; wherein Rxe2x80x2 is C1-C12 linear or branched alkyl), amino, C1-C12 mono- and dialkylamino, and mixtures thereof
Fragrance Release Half-life
The cyclic pro-perfumes and other pro-accords useful in the fragrance delivery systems of the present invention generally have a delayed release of final fragrance accord in order to achieve the increased fragrance longevity benefits described herein. However, the pro-accords generally also deliver the fragrance accords during a time period useful to the formulator, for example, within a time period desirable to the consumer.
For the purposes of the present invention the pro-accords generally have a xe2x80x9cFragrance Release Half-lifexe2x80x9d of less than or equal to 12 hours when measured in NaH2PO4 buffer at pH 2.5 and greater than or equal to 0.1 hour when measured in NaH2PO4 buffer at pH 5.3. The xe2x80x9cFragrance Release Half-lifexe2x80x9d is defined herein as follows.
Pro-accords deliver their corresponding mixture of fragrance raw materials or fragrance accords according to the equation:
Pro-Accordxe2x86x92Accord
wherein the accord which is released may be a binary accord or a multiple fragrance raw material accord.
The rate at which the accord is released is defined by the formula:
Rate=k[Pro-accord]
and can be further expressed by the formula:       -                  ⅆ                  [                      Pro            ⁢                          -                        ⁢            accord                    ]                            ⅆ        t              =      k    [          Pro      ⁢              -            ⁢      accord        ]  
wherein k is the release rate constant and [Pro-accord] is the concentration of pro-accord. For the purposes of the present invention the xe2x80x9cFragrance Release Half-lifexe2x80x9d, txc2xd, is related to the release rate constant by the formula:       t          1      /      2        =      0.693    k  
and this relationship is used for the purposes of the present invention to determine the xe2x80x9cfragrance Release Half-lifexe2x80x9d (FRHL).
Due to the hydrophobic nature of some pro-accords, it is necessary to conduct the determination of txc2xd and k in a mixture of 90/10 dioxane/phosphate buffered water. An example of the procedure used to measure the suitability of a pro-accord for use in the fragrance delivery systems at pH 2.5 is as follows. The phosphate buffered water is prepared by admixing 3.95 mL of 85% phosphoric acid (H3PO4) and 24 g of sodium dihydrogen phosphate (NaH2PO4) with one liter of water. The pH of this solution is approximately 2.5. Next 10 mL of the phosphate buffer is admixed with 90 mL of dioxane and the pro-fragrance to be analyzed is added. The hydrolysis kinetics are then monitored by conventional HPLC at 30xc2x0 C.
The pro-accord component of the present invention, in order to assure the stability of acid labile pro-accords, may include a source of reserve alkalinity equivalent to at least 0.001 molar (1 milli-molar) sodium hydroxide. This reserve alkalinity generally serves to prevent premature release of the fragrance raw materials by the pro-accords prior to exposure of the pro-accords to skin. For the purposes of the present invention the term xe2x80x9ca reserve alkalinity of at least 0.001 molarxe2x80x9d is defined as xe2x80x9cthe amount of alkaline material present in one liter of the second component when placed in an equivalent volume of water, would produce a hydroxide ion equivalent of 0.001 moles or greaterxe2x80x9d. By way of illustration, 0.0004 g of NaOH present in a 10 mL aliquot of the second component would produce a reserve alkalinity of at least 0.001 molar.
Suitable sources of alkalinity are the alkali metal and alkali earth hydroxides. For example, sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, sodium carbonate, potassium carbonate, and sodium silicate. However, other suitable sources of alkalinity can be used which are compatible with the pro-accords of the xe2x80x9cpro-accord componentxe2x80x9d.
In addition, the fragrance delivery system of the present invention may be suitably use in a fine fragrance composition. Said perfume compositions provide extended fragrance character impressions, and comprise:
A) a pro-accord component comprising:
i) from 0.1% to 99% by weight, of one or more pro-accords formed from at least one fragrance raw material, said pro-accord releasing upon hydrolysis at least two fragrance raw materials selected from the group consisting of primary, secondary, and tertiary alcohols, aldehydes, ketones, esters, carbonates, and mixtures thereof, provided each pro-accord:
a) is formed from at least one fragrance raw material having a molecular weight greater than or equal to about 100 g/mol;
b) has a molecular weight greater than or equal to about 300 g/mol;
c) has a molecular weight at least two times greater than the lowest molecular weight fragrance raw material which comprises said pro-accord;
d) has a fragrance release half-life of less than or equal to about 12 hours at pH 2.5 or greater than or equal to about 0. 1 hour at pH 5.3 when measured in NaH2PO4 buffer;
ii) the balance carriers, stabilizers, and other adjunct ingredients whereby said pro-accord component is provided with an amount of reserve alkalinity equal to at least 0.001 molar NaOH;
B) a fragrance raw material component comprising:
i) from 0.1% to about 99% by weight, of a mixture of base note fragrances;
ii) from 0.1% to about 99% by weight, of one or more top and middle note fragrances;
ii) the balance carriers, fixatives, and other adjunct ingredients; and
C) from 0.1% to about 99% by weight, of a cyclic pro-perfume component comprising one or more of the cyclic pro-perfumes described herein.
The following are examples of cyclic pro-accords of the present invention which release fragrance raw materials.